1. Field of the Invention
The present invention relates to a self-aligning bearing assembly including a bearing retainer which changes its form to compensate for a bearing having an irregular profile.
2. Description of the Prior Art
The use of self-aligning bearing assemblies is known in the art. Such assemblies include a support having a recess in which a bearing rests, the bearing being retained in place by a retaining member which engages the surface of the bearing to sandwich the bearing between the support and the retaining member. The retaining member is affixed to the support to hold the bearing in place relative thereto. Such an assembly is used to support a rotatable shaft on a fixed structure. Examples of such self-aligning bearing assemblies are to be found in U.S. Pat. Nos. 2,813,762 to Bridenbaugh and 2,938,755 to Lee et al. In these patents, a bearing is described having a bore which extends generally perpendicular to the support. A rotatable shaft extends through the bore and through an opening in the support in such a manner that the shaft is generally oriented perpendicular to the support.
A somewhat related structure is to be found in U.S. Pat. No. 4,074,158 to Cole. This patent describes an electric motor having a motor shaft which is supported by self-aligning bearings which are sandwiched between retaining members and a portion of the rotor assembly.
In other known similar self-aligning bearing assemblies the bearing is completely supported by a retaining member having a plurality of fingers which extend therefrom at oppositely and alternately spaced positions to engage the bearing surface. Examples of such self-aligning bearing assemblies are to be found in U.S. Pat. Nos. 1,924,072; 3,701,574; and 3,754,802, to Lavigne, Phillips and Keller, respectively.
A somewhat related structure is to be found in U.S. Pat. No. 3,770,990 to Winkelmann. This patent describes a bearing structure for a rotatable shaft wherein the assembly includes a splitring bearing. Each section of the bearing is retained by a respective retainer ring having a plurality of circumferentially spaced fingers which extend radially to provide a bearing cage for the respective bearing section.
The primary function of a self-aligning bearing assembly is to provide precise alignment of a rotating shaft relative to the structure to which it is affixed. It is typical to construct such assemblies using spherical or partially spherical bearing members or bearing members in the form of a cylindrical sleeve which have been molded from powdered metal. For examples, it is known to construct such bearing members from ferrous or non-ferrous materials such as powdered iron, iron-bronze or bronze. In producing such a bearing member by molding, compressed powder metal is tamped into two mold halves which are closed together in a known manner. When the bearing member is removed from the mold, there is a tendency for a mismatch to occur at the parting line between opposing halves of the molded bearing. For example, FIGS. 1 and 2 schematically depict a bearing in the form of sleeve bearing 2 which has been molded from powder metal in a known manner, bearing 2 including opposing halves 4 and 6. It will be noted that the two halves are offset or mismatched at the parting line 8. Such a mismatch has an adverse affect upon the comptability of the bearing with the bearing retainer and base or housing. In particular, when the bearing is mounted such that the bore 10 through which the rotatable shaft 12 extends is horizontal relative to a supporting surface 14 depicted in phantom lines in FIG. 2, it is difficult, if possible at all, to use sufficient even pressure to retain the bearing in place and yet allow the bearing to inherently self-align.
It is highly desirable to provide a self-aligning bearing assembly capable of functioning in a satisfactory manner notwithstanding that the bearing has been molded from power metal such that there is a mismatch at the parting line between opposing halves of the molded bearing.
It is also desirable to provide a self-aligning bearing assembly and retainer member therefor which compensates for an irregular bearing profile.
It is further desirable to provide a retaining member, for use in a self-aligning bearing assembly, which retains a bearing having an irregular profile in place using constant pressure and yet allows the bearing to inherently self-align.